Fluid filters



April l, 1958 E. J. VAN LIER ET AL 2,828,863

FLUID FILTERS Filed March 12, 1956 z WFIVIIIMMMUl/M ATTORNEYS FLUID FILTERS Emil J. van Lier, Martinsville, and Frank R. Gensicke,

Roselle, N. J., assignors to Komline-Sanderson Engineering Corporation, Peapaclr, N. J., a corporation of New Jersey Application March 12, 1956, Serial No. 570,739 13 Claims. (Cl. 210-130) This invention relates to fluid filters of the type in which the fluid isvforced under pressure through one or more filter elements and, more particularly, relates to the provision in such a filter of means for causing any high pressure back surges of the filtered fluid to fiow around and by-pass the filter elements.

lt has been common practice in fluid filters to place one or more hollow replaceable filter units in a filter chamber adapted to receive uid under presure. Such filter elements normally are provided with discharge or effluent tubes which project through openings in a division plate or partition to establish communication between the interiors of the several filter elements and an efiiuent chamber disposed on the opposite side of the partition from the filter chamber. lt will be understood that the filtered fluid, after being received in the eiuent chamber, is then drawn off through a suitable pipe or conduit.

Under normal operating conditions the fluid pressure in the filter chamber substantially exceeds that in the eli'iuent chamber, thereby causing the uid to pass through the hollow filters and into the interiors thereof, thence through their respective effluent tubes into the efliuent chamber. The filtering elements generally are provided with hollow walls which are filled with filtering paper or other frangible filter material. During the use of such filters the outow of filtered fluid from the efiiuent chamber may be quickly cut off at times by the rapid closing of a valve on the outflow side of the efiiuent chamber, thus resulting in a momentary back surge of pressure which greatly exceeds the pressure within the filter chamber. The resulting backflow of the filtered fluid at high pressure into the filter elements thus frequently ruptures the filter paper or other filtering agent in these elements, rendering them useless for further service and permitting unfiltered fiuid to pass through them if they are inadvertently continued in use.

lt is primarily to remedy the foregoing defects that the present invention has been conceived.

lt is a primary feature, therefore, of the present invention to provide a positive static seal between the efiiuent tube of each filter element and the opening in the partition through which it passes, such seal being arranged to positively withstand pressure from the filter chamber, but to function as a check valve and permit a backtiow of iiuid from the efiiuent chamber into the filter chamber responsive to such back pressure surges.

lt is a further object of the invention to provide such a combined seal and valve which may be readily applied to and removed from the filter unit, as an incident to applying or removing the filter element with which it is associated.

Normally, the filter elements will rest on the division plate or partition with their effluent tubes projecting in sealed relation downwardly through the openings in such partition, the lower end of the filter element in such case projecting laterally outwardly beyond the opening and normally resting on the division plate around said opening in such a position as will obstruct the back flow of nited States Patent" 2 fiuid. tion to mount each such filtering element, together with its eiuent tube and seal, for limited vertical movement in the filter chamber responsive to such back pressure of the fluid, whereby the lower end of the filter element will be moved away from the back flow passage to relieve the obstruction thereof.

By incorporating such back flow or pressure relief function in the seal for the effluent tube of each filter element and thereby permitting the back fiowing uid to escape through an annular path completely surrounding the efiiuent tube, it has been found that each of the several combined seals and valves, by permitting the back flow of a comparatively large volume of fluid therethrough, will rapidly relieve the pressure resulting from back surges of filtered fluid, thereby preventing the building up of such back pressure to a point where it might damage the filter elements.

Further objects and advantages of the invention will be readily apparent from the following description of the preferred embodiment of the invention in conjunction with the accompanying drawings in which:

Figure 1 represents a side elevation, partly in section, of a complete filtering unit incorporating the improvements constituting the subject matter of the invention;

Figure 2 is a plan view of the filtering unit shown in Figure l; and

Figure 3 is an enlarged fragmentary section through the lower end of one of the filter elements and its associatedV portion of the partition.

Referring now in detail to the accompanying drawings: The reference character l0 generally designates the filter case or vessel which may conveniently be of cylindrical construction and supported in an axially vertical position by the several legs l2. The lower end of this housing 10 is closed by a permanently secured dome-shaped bottom 14 which will preferably be provided with a drain opening normally closed by a threaded plug 16,'iii ac-4 lar fiange 2t) which may be bolted to a similar flange 22` secured around the upper end of the housing 10, a gasket Z4 preferably being interposed between these flanges to insure a fluid-tight connection. Preferably, the cover 18 will be provided with an ai-r vent which will normally be closed by a threaded plug 26.

Adjacent the bottom of the housing or vessel 10, there is provided a horizontal partition or division plate 28, the outer periphery of which is welded or otherwise secured in fiuidtight relation to the inner face of the housing lil, to thus divide the interior of the housing or vessel lt) into a filter chamber fifi above the partition and an eiiiuent chamber or discharge manifold 32 disposed below the partition 28. Communication between these two chambers may occur as hereinafter described, through one. or more circular openings 3ft in partition 23'. (See Figure 3.) Disposed in the filter chamber, with their lowerends supported on the partition 2S, and their efiiuent oroutflow tubes projecting in sealed relation through the re ;4 spective openings 34 are one or more hollow filter ele ments of conventional construction, each designated 36. By reference to Figure 3, it will be seen that-each' of such filter elements 36 comprises inner and outer perforated cylindrical walls 38 and 40, respectively, .definingy an annular space closed at opposite axial ends by the endl plates 42 and 44, respectively. Confined insuch annular space Yis the filtering material which will generally conf sist of multiple thicknesses of filter paper 39. Whiley It is an important additional feature of the inven-l tlreupper end of the inner wall or tube 38 is closed by the upper end plate 42, the lower end of this tube communicates with the etiiuent tube 46 which preferably is formed as an integral part of the lower end plate 44 and which extends 'in normally sealed relation through one of the openings 34 in partition 28 to establish communication between the etiiuent chamber 32 and the interior of the filter element. ri`hus, it will be seen that the pressurized fiuid in the filter chamber 30 will pass through the perforated walls 38 and 40 and the intervening filter paper 3? to the interior of the cylindrical wall or tube 38, thence through the tube 46 into the efiuent chamber 32.

A hold-down plate 48 fixed at the upper ends of the filter chamber, is positioned to engage the upper ends of the several iilterelernents 36 to prevent such substantial upward movement of these elements, responsive to back pressures of the ltered fluid, as might retract their eiiiuent tubes 46 with their associated seals from their sealing relation in the respective openings 34. However, hold-down plate 48 will preferably be spaced above the division plate or partition 28 a distance somewhat greater than the lengths of the filter elements 36 to permit a limited amount of upward movement of these elements. Thus the lower ends of the filter elements 36 may be raised clear of the partition 2S responsive to excessive back pressures of the filtered fluid, such as above-mentioned, to permit removal of the said lower ends from obstructing relation relative to the openings 34.

The hold-down plate 48 will preferably be removably supported on angle brackets 49 welded or otherwise secured within the vessel 1G. For the purpose of securing the hold-down plate 4S against upward displacement, same is secured in place by means of bolts S1 projecting upwardly through openings in the plate, together with cooperating Wing nuts S3, as will be readily apparent from inspection of Figure 1.

Referring again to Figure 3, it will be seen that each of the efiiuent tubes 46 is of somewhat smaller diameter externally than the opening 34 in which it is received. Thus, its outer wall is radially spaced from the peripheral wall of the opening 34 and cooperates therewith to define an annular back liow passage 50 from the eiuent chamber 32 to the filter chamber 30.

An annular exible seal 52 of the one-way flow type is disposed in this back flow passage 56 to prevent flow therethrough ofk unfiltered fluid from the filter chamber 30, but to permit a backflow of the filtered uid whenever the back pressure of fluid in the effluent chamber 32 appreciably exceeds the fluid pressure within the filter chamt ber. Thus, it will be seen that the seal 52 is operative to relieve excessive pressures occurring within the efiiuent chamber 32 by permitting the filtered fluid to flow back directly into the filter chamber, bypassing the filter element 36 and thereby avoiding likelihood of damage to 1 such element through rupturing or otherwise damaging the lterpaper 39.

Preferably, the seal 52 is carried by the eiuent tube 46 of the filtering element and is axially slidably removed and replaced in opening 34 as an incident to removal or replacement of the element 36. For this purpose the effluent tube 46 of each element is formed externally with an annular groove which is defined by upper and lower annular abutrnents S4 and 56, respectively, and a cylindrical inner wall S8.

"Ihe seal 52 which may be formed of synthetic rubber or the like, comprisesintegrally interconnected and concentrically related iiexible sealing flanges 60 and 62 projecting upwardly from a base `ring Vportion 64 at their point of juncture. It will be seen that this base ring 64'is at least partially received in the annular groove in `engagement with the lower annular abutment 56, which thus positions the seal 64 against downward displacement by the 'fluid rpressure thereabove. The two flanges 60 and 62 'both project'upwardly 'fromth'e base ring 64 toward the filter chamber 30. The inner flange 60 .is inclined radially inwardly with its free edge normally in engagement with the cylindrical wall 58 at the bottom of the annular groove in tube 46. It will be seen that the upper wall or abutment 54 of said groove will limit the upward movement of the seal 52 responsive to fluid pressure from therebeneath. The outer flange 62 of the seal is inclined radially outwardly with its free edge normally in sealing engagement with the cylindrical inner wall or periphery of the opening 34.

Sincethe partition 28 is of substantial thickness, it will be seen that the inner wall of the opening 34 will be of substantial axial extent for proper cooperation with the seal 52 during the limited upward displacement of the element and seal. Due to the inclined upwardly divergrelation or' the flanges 60 and 62 and their flexibility, it will be readily apparent that the normally predominant fluid pressure within the filter chamber 30 will urge these vfranges 6i) and 62 into fluid-tight sealing engagement with their cooperating walls; that is, with the periphery of opening 34 and with the inner wall 58 of the groove, respectively. However, a back pressure in the effluent chamber 32 appreciably in excess of the pressure within the filter chamber, will urge at least one of these flanges, more particularly, the flange 62, away from sealing relation with its cooperating wall surface to permit a back flow of filtered uid into the filter chamber.

It will thus be readily apparent in the operation of the filter unit in its entirety, that such unit will operate in more or less usual manner under conventional conditions, wherein the pressure within the filter chamber 30 exceeds that within the efliuent chamber 32. Normally, fluid will be delivered under pressure through an inflow pipe 64, which extends through both the housing bottom 14 and the partition 28. Such fiuid, after being filtered through the walls of the several filter elements V36, will then pass downwardly through the interiors thereof and through the effluent tubes 46 of the respective elements into the eliiuent chamber 32, from whence it will be drawn away through a discharge pipe 66 shown in Figure 1. However, in the event of a sudden blocking of the flow of the uid from the efduent chamber as by the sudden closing of a valve, with the resultant build-up of fluid pressure in the effluent chamber in excess of that in the filter chamber, the ltered fluid in the effluent chamber 32 will be Ycaused to ow upwardly through the passages 50 into the filter chamber 30, thus yrelieving the pressure vand avoiding damage to the filter elements 36. Moreover, the increasing pressure will be exerted against the seals 52 and the elements 36 to raise the lower ends of such elements clear of the partition 28 and thereby provide a comparatively unobstructed path for the upwardly flowing fluid as it emerges through the passages 50. Also, such upward movement of the respective lter elements 36 will, to some extent, contribute toward reduction of the pressure within effluent chamber 32.

In this application, we have shown and described only the preferred embodiment of the invention. However, we recognize that the invention may assume other embodiments and that its several details may be modified in various ways, all without departing from our inventive concept. Accordingly, the drawings and description are to be considered asmerely illustrative in nature.

Having thus described the invention, what is desired to be Asecured by Letters Patent is:

l. A fluid filter comprising a duid-tight vessel, a partition within said vessel dividing same into a lter chamber and an efiiuent chamber, said partition being formedwith a circular opening therethrough, a hollow filter element in said filter chamber including an effluent tube extending through said opening and establishing communication between said efliuent chamber and the hollow interior of said filter element, said efiiuent tube being spaced radially inwardly `from the periphery of said opening and thereaeaasea with defining an annular backflow passage between said chambers, and an annular flexible seal of the one-way flow type disposed in said backow passage to prevent the flow therethrough of fluid from the filter chamber, and to permit a baclrflow of fluid from the eliiuent chamber to the filter chamber when the fini-d pressure in die eflluent chamber appreciably exceeds that in the filter chamber.

2. A fiuid filter comprising a fiuid-tight vessel, defining a filter chamber adapted to receive fluid under pressure, and formed with a circular outlet opening, means defining an efluent chamber communicating with said opening, a hollow filter element in said filter chamber including an effluent tube extending through said opening and establishing communication between said effluent chamber and the hollow interior of said filter element, said efiiuent tube being spaced radially inwardly from the periphery of said opening and therewith defining an annular backiiow passage between said chambers, and an annular flexible seal of the one-way flow type disposed in said backfiow passage to prevent the iiow therethrough of fluid from the filter chamber, and to permit a backflow of fiuid from the efliuent chamber to the filter chamber when the fluid pressure in the efiiuent chamber appreciably exceeds that in the filter chamber.

3. The combination of claim 1 wherein said partition extends horizontally, and the lower end of said filter element rests on said partition around said opening, said filter element being free to move upwardly a predetermined extent above said partition, when the fluid pressure in the efiiuent chamber exceeds that in the filter chamber, thereby reducing the obstructing effect of said lower end on the backow of fluid from said opening.

4. The combination of claim 3 wherein the seal is carried by the eliiuent tube for vertical movement therewith.

5. A fluid filter comprising a liuid-tight vessel defining a filter chamber for receiving iiuid under pressure, and formed with an outlet opening, a hollow filter element in said chamber having an efiiuent tube projecting into said opening, said tube being spaced inwardly from the periphery of said opening and therewith defining a backow passage around the tube, and a fiexible seal in said backow passage preventing the flow of fluid therethrough from the filter chamber but permitting the backflow therethrough toward the filter chamber of fiuid at a higher pressure than the fluid in the filter chamber.

6. The combination of claim 5 in which said outlet opening is formed through a generally horizontal portion within the vessel, and said lter element rests on said portion around said opening, said filter element being free to move away from the opening to uncover same responsive to the pressure of said backfiowing fluid.

7. The combination of claim 6 wherein the said seal is carried by the efiiuent tube for movement therewith through the said opening.

8. The combination of claim 7 including means for normally limiting such movement of the filter element to prevent retraction of the seal from said opening.

9. The combination of claim 5 wherein said flexible seal is of annular configuration comprising inner and outer flexible sealing flanges having free marginal edges projecting toward said filter chamber, the inner flange being inclined inwardly toward said eiiiuent tube, and the outer flange being inclined outwardly toward the periphery of said opening, whereby the fluid pressure withinA said filter chamber will normally urge said fianges into sealing relation with the said tube and the said periphery respectively, but a back pressure in said opening in excess of the pressure within said chamber will urge at least one or' said flanges out of its said sealing relation to permit a backfiow of fiuid into the filter chamber.

l0. The combination comprising an enclosed chamber having an opening, a fluid treating element within said chamber having an eiiiuent tube extending into said opening, said tube being spaced inwardly from the periphery of said opening and therewith defining a backfiow passage exteriorly of said tube, and a fiexible annular seal in said passage preventing the flow of fluid therethrough from the filter chamber, but permitting the iiow of fluid from said passage into the chamber through a path which by-passes said fiuid treating element.

11. The combination of claim 10 including means carried by said tube for axially positioning the seal thereon, said seal being movable through the opening with said tube.

12. The combination of claim l0 wherein said annular seal includes relatively diverging inwardly and outwardly axially inclined sealing fianges having their free edges projecting toward said chamber, and respectively engaging said tube and the periphery of said opening.

13. In a device of the character described, a plate formed with a circular opening therethrough, a tube extending and movable axially within said opening in concentric radially inwardly spaced relation to the periphery of said opening and with said periphery defining an annular passage, means fixed to the tube outside of said annu- Vlar passage and movable with the tube to obstruct said passage, and a flexible annular seal carried by and movable axially with the tube in said passage, said seal comprising relatively diverging inwardly and outwardly axially inclined sealing flanges having their free marginal edges projecting in the same axial direction and respectively engaging said tube and said periphery.

References Cited in the file of this patent UNITED STATES PATENTS 280,212 Miles June 26, 1883 2,507,125 Townsend May 9, 1940 2,575,900 `Vokes Nov. 20, 1951 2,576,810 Ratelband Nov. 27, 1951 2,734,636 Foster Feb. 14, 1956 2,743,737 Textor May 1, 1956 FOREIGN PATENTS 697,816 Great Britain Sept. 30, 1953 

